The molecular motor Myosin Va interacts with the cilia-centrosomal protein RPGRIP1L

L H P Assis,J Kobarg,T D Melo-Hanchuk,P S L Oliveira,P O Giuseppe,M T Murakami,E M Espreafico,D M Trindade,M R Alborghetti,A F Z Nascimento,C T Santos,R E Larson,R V Honorato,C C C Tonoli,R M P Silva-Junior,L G Dolce

doi:10.1038/srep43692

L H P Assis, J Kobarg + Show 14 more

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https://doi.org/10.1038/srep43692

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Myosin Va (MyoVa) is an actin-based molecular motor abundantly found at the centrosome. However, the role of MyoVa at this organelle has been elusive due to the lack of evidence on interacting partners or functional data. Herein, we combined yeast two-hybrid screen, biochemical studies and cellular assays to demonstrate that MyoVa interacts with RPGRIP1L, a cilia-centrosomal protein that controls ciliary signaling and positioning. MyoVa binds to the C2 domains of RPGRIP1L via residues located near or in the Rab11a-binding site, a conserved site in the globular tail domain (GTD) from class V myosins. According to proximity ligation assays, MyoVa and RPGRIP1L can interact near the cilium base in ciliated RPE cells. Furthermore, we showed that RPE cells expressing dominant-negative constructs of MyoVa are mostly unciliated, providing the first experimental evidence about a possible link between this molecular motor and cilia-related processes.

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Class V myosins are motor proteins that transport and/or tether vesicles, organelles and macromolecules, using the energy of ATP hydrolysis to walk toward the plus end of actin filaments[1]
As myosin Va (MyoVa)-globular tail domain (GTD) can be phosphorylated on residue S1652 by calcium/calmodulin-dependent protein kinase II (CaMKII)[34,35], which results in its release from melanosomes and inhibition of melanosome transport[36], we investigated whether S1652 phosphorylation could affect RPGRIP1L binding
We revealed that MyoVa interacts with the cilia-centrosomal protein RPGRIP1L at the centrosome

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Class V myosins are motor proteins that transport and/or tether vesicles, organelles and macromolecules, using the energy of ATP hydrolysis to walk toward the plus end of actin filaments[1]. The partial albinism is due to a defect in the capture and transport of melanosomes by the protein myosin Va (MyoVa) in melanocytes[3,8], whereas the neurological impairment has probably pleiotropic origins, considering the several functions reported for MyoVa in the brain[6]. These functions include regulation of the exocytosis of large dense-core vesicles[9,10], the transport of endoplasmic reticulum into Purkinje cell dendritic spines[11] and the targeting of proteins involved in signaling pathways that control neuronal cell size and shape, such as PTEN12 and RILPL213. This paradox has been changing with the recent discovery that the centrosome is an actin-organizing center[24], which correlates with the abundant presence of the actin-based motor MyoVa at this organelle

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